1. Field of the Invention
The invention relates to an improved developing device for an image forming apparatus, such as a copier, facsimile machine, printer, etc.
2. Discussion of Background
A conventional developing device for an image forming apparatus utilizes a dry-type toner to form or develop an image, with the image forming apparatus including a developing sleeve for carrying toner thereon, and with the sleeve disposed adjacent to a photosensitive drum. A magnet roller is disposed inside of the sleeve member, and parallel to the axis of the sleeve member. The magnet produces a magnetic force such that toner on the sleeve forms a magnetic brush which develops a latent image formed on the photosensitive drum.
With such a device, a bearing for the sleeve is disposed outside of the magnet roller (i.e. in the axial direction of the magnet roller), with an edge of the sleeve member outside of the bearing. In addition, a supporting part for the axle or axis of the magnet roller is disposed outside of the edge of the sleeve member (an example of such an arrangement is shown in Japanese Patent Publication No. 41-3428/1966, or Japanese Patent Publication No. 62-57991/1987). As a result, the width of such a developing device is necessarily larger than that of the latent image area which is developed by the developing device. Accordingly, it is difficult to minimize the size of the developing device, although the size of many other parts of the image forming device have recently been reduced.
Another concern with developing devices resides in the avoidance of deterioration of toner accommodated in the toner container, which deterioration can be caused by the conveying mechanism installed in the toner supplying container. An arrangement which attempts to avoid this problem includes a toner container which accommodates the toner, with an outlet at a lower part of the toner container, and a magnetic member disposed adjacent the outlet such that toner falls by gravity through the outlet, without requiring a toner conveying member. An example of this type of arrangement is shown in Japanese Patent Publication No. 58-52587/1983. However, with such a device, toner scattering occurs as a result of vibrations which occur in the machine during developing, and the scattering toner can cause contamination of the surrounding parts or components of the device.